Cytomegalovirus Retinitis During Idecabtagene Vicleucel Therapy in Patients With Relapsed/Refractory Multiple Myeloma.

Background: Chimeric antigen receptor T-cell (CAR-T) therapy has improved outcomes in patients with triple-class-exposed relapsed/refractory multiple myeloma (RRMM); however, it is associated with complications, including infections. Cytomegalovirus (CMV) infection is one of the infections associated with idecabtagene vicleucel (ide-cel) treatment. While there have been several reports on CMV replication, CMV retinitis has only been documented in case reports, making it a severe but under-reported complication.

Methods: This retrospective single-institution study was conducted at the Japanese Red Cross Medical Center. The study analyzed the clinical features of CMV retinitis in 53 patients with RRMM treated with ide-cel between December 2022 and December 2024. CMV retinitis was diagnosed based on ophthalmological findings, with CMV polymerase chain reaction (PCR) confirmation in the vitreous fluid, if necessary.

Results: The cumulative incidence of CMV retinitis at 6 months was 9.2%, with a median onset time of 2.2 months postinfusion. Among the four patients with CMV retinitis, three patients experienced visual impairment and one patient was asymptomatic. One patient was diagnosed with CMV retinitis, despite having negative serum CMV PCR results, which highlights the limitations of replication-based screening. All patients required treatment, with one patient achieving improvement and three patients undergoing ongoing treatments.

Conclusions: CMV retinitis is a significant complication of ide-cel therapy. Regular CMV PCR is important, but early ophthalmological consultations are crucial for timely detection and management, even in the absence of CMV replication, particularly when visual impairment develops. Further studies are needed to identify the risk factors and establish preventive strategies.